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Making connections at the neuroscience meeting

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By Becky Oskin

Babies are natural-born scientists, able to take in and synthesize what would be an overwhelming amount of information for a grown-up. That talent would come in handy for adults at the Society for Neuroscience’s annual meeting, held from November 13-17 in California, where several thousand posters and presentations vie for guests’ attention.

With 30,000 people expected to attend, the networking alone can eat up any chance to catch more than the essential talks in your specialty. So, whether you are overwhelmed with options or simply unable to attend, we’ve got the scoop on the hottest areas of neuroscience under the San Diego sun.

The developing brain

Early childhood experiences, both good and bad, influence the brain for a lifetime. For example, scientists know that extreme stress, such as child abuse, affects whether certain genes related to stress response get switched on or off, a phenomenon called epigenetics. Regina Sullivan of New York University speculates that child abuse-related epigenetic changes, which alter the brain, are passed on to the next generation, perhaps explaining the cycle of abuse observed in many families.

The primary evidence for stress-related changes comes from human brain imaging, which has uncovered brain differences between children with a typical childhood and those who suffer abuse. But expect to see several reports based on mouse models at the meeting. The animal models will help further assess the impact of both genetic and environmental factors on childhood development.

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“There is very exciting work that is being done documenting the negative consequences of early childhood adversity,” says Bruce McEwen, the Alfred E. Mirsky professor of neuroscience at Rockefeller University in New York.

McEwen’s work shows that the effects of toxic childhood experiences can be reversed through interventions such as high-quality early care and education programs. Documenting the biological changes caused by childhood stress will help efforts to fund such interventions. “The fact that these are very real biological effects makes it more poignant and attracts attention to them,” he says.

Changing the childhood brain is also a hot topic in research on autism spectrum disorders, thanks to new discoveries in synaptic plasticity. Problems with synapses, the connectionsbetween nerve cells, appear to underlie autism and related neurodevelopmental diseases.

A growing number of studies indicate that synapses can change their shape and function over time, a phenomenon known as synaptic plasticity. These observations bring renewed interest in cognitive training and behavioral interventions for autism – perhaps the brain can be taught to compensate for problems caused by autism.

Computational neuroscience

Encompassing both modeling and experimentation, computational neuroscience includes everything from decoding memory to theinput and output of single neurons.

One topic to watch is modeling signal transfer patterns throughout the brain. New techniques make it possible to simultaneously record signals from many neurons, and to selectively stimulate or silence specific neurons. The sensitivity means scientists can, for the first time, watch the output from a neuron spread through the brain.

“What is exciting for me is we can now go in and record and stimulate individual neurons and find out what effects they have downstream,” says Terry Sejnowski, professor and head of the computational neurobiology lab at the Salk Institute in La Jolla, California.

“The function of a neuron depends on its output. If it projects to the brain region known as the calcarine sulcus, maybe it is helping to guide eye movement, but if it projects to the hippocampus, maybe it is important for longterm memory. Experimentally, that has been very, very difficult to work out.”

Researchers are also beginning to see that neurons respond differently to different stimuli. For example, signals required to move a prosthetic arm can change when people are tired or stressed, and may even be different when hooked up to the brain interference. Such observations will help improve brain-machine interferences such as prosthetic limbs and thought-controlled wheelchairs.

Sejnowski says some of the most intriguing results in computational neuroscience come from collaborations between modelers and experimentalists. “It is becoming obvious now that these cooperative partnerships are providing an unfair advantage for the labs that are taking advantage of the insights computational analysis can provide,” he says.

For Sejnowski and his computational colleagues, collaboration means finally having human data that confirms their computer models of sleep spindles, oscillations during sleep that are thought to contribute to memory consolidation. “This is something I’ve been working on for 20 years and it’s the first time we have data from humans,” he says.

Neuroethics

Today’s discoveries in neuroscience can quickly be applied to daily life. But should they be?

One of the leaders in the ethics of neuroscience, Hank Greely, will address such fundamental issues at the meeting. Greely, the Deane F. and Kate Edelman Johnson professor of law at Stanford University, will outline several broad categories he believes scientists and ethicists need to address. His favorite to discuss is mind-reading&colon; using scanners to gauge what someone is thinking and feeling.

Researchers can already probe whether people are telling the truth, as well as how they feel about certain people or pictures, and even detect if they intend to move their right or left hands. What happens when brain scans are used to extract information someone wants to keep private? Could scanners replace torture?

The lack of answers hasn’t stopped neuroscience from showing up in courtrooms. Brain scans have been widely used in criminal cases, but Greely points out that scans could alsoprovide evidence for more everyday situations,such as deciding whether someone receiving worker’s compensation truly suffers ongoing pain from an on-the-job injury.

“We are not great mind readers now, but if we get better, it is bound to affect society,” he says. Greely urges scientists to actively engage the public in discussing the implications of cuttingedge neuroscience.

“I have to believe that we are more likely to deal well with a problem if we have dealt with it in advance,” he says. “Neuroscientists are uniquely well placed to help point out possible problems and put them in perspective.”